I just bought this game yesterday, installed it, go to create account- Invalid authentication key. Tried it several times, but no go. My only guess is, they cleared all the old keys from their database, and this copy I purchased had been sitting on the shelves forever. It was the only copy in the store. (Best Buy)
I wrote Blizzard, then I read on a faq page about what I have to go through to get this key working. I don't. I get another key, either buy swapping out the game at the store for another one (IF they let me), or pay $10 for Blizzard to do it for me. This is my 4th MMORPG I've played and I've never had a problem with the key, nor seen the horrible manner in which discrepancies are solved. Its their screwup. Why should I have to do all the leg-work? I've read on many pages what horror stories others have had in dealing with their support people.